#include<stdio.h>

int main(void)
{
	double w,p,sum=0.0;
	
	while(scanf("%*s%lf%lf",&w,&p)!=EOF)
	{
		sum+=w*p;
	}
	
	int fen;
	int dada=(int)(sum*100);
	fen=dada%10;
	
	if(fen>=5)
	{
		printf("%.1lf",((dada/10)+1)*0.1);
	}
	else
	{
		printf("%.1lf",dada/10*0.1);
	}
	
	return 0;
}

